Juniper JUNOSE 11.1.X MULTICAST ROUTING, Руководство по настройке

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Data MDT Receivers
When the Receiver C-PIM-SM receives a <C-SG, P-G> MDT Join TLV message from
the default MDT, it extracts the C-SG and the data MDT P-Group address from the
TLV and queries the route map that you specified for the data MDT to determine
whether the C-SG is a candidate for a data MDT. If it matches, the C-PIM-SM adds
the MDT Join TLV to its database and records the time.
If the Receiver C-PIM-SM does not receive an MDT Join TLV<C-SG, P-G> to refresh
its database within the amount of time specified for the timeout in the
mdt-data-timeou t command, the MDT Join TLV<C-SG> is removed from the
database and the associated data MDT is removed.
When a new MDT Join TLV<C-SG, P-G> is added to the database, the Receiver
C-PIM-SM determines whether it has an SG, SPT state. If it has an SG state, and the
incoming interface (IIF) is the default MDT, then C-PIM-SM creates the data MDT and
deletes the corresponding forwarding entry. C-PIM-SM waits for the source to transmit
data on the data MDT. During this period, data can continue to be received on the
default MDT. C-PIM-SM fails the reverse-path forwarding (RPF) check, which results
in a forwarding entry with a discarded IIF.
If the C-SG,SPT state is created (either as a result of a C-SSM join or switch from RPT
to SPT), and it is the default MDT, the Receiver C-PIM-SM determines whether an
MDT Join TLV<C-SG> is active. If it is, C-PIM-SM creates the data MDT.
Establishing a Data MDT Using ASM or SSM
A data MDT carries one C-SG flow. If the data MDTs are established using any-source
multicast (ASM), then the P-Group address selected by a PE for the data MDT must
be unique to that PE in the MDT (that is, the range of MDT P-Group addresses available
in the core must be administratively divided among all the PEs that will source VPN
multicasts). The VRFs in a PE must share the P-Group addresses in the assigned range
for the PE.
If the data MDTs are established using single-source multicast (SSM), you must
configure VRFs to transmit on a tunnel using the same MDT P-Group address. Each
VRF transmits using a unique P-Source address; however, each data MDT created
by the VRF must use a different P-Group address. There might be one sender data
MDT and possibly many receiver data MDTs sharing an IP tunnel. Each PE can assign
MDT P-Groups from the same range, but the P-Group addresses must be
administratively divided among the VPNs.
For a receiver on the data MDT, P-PIM-SM joins the data MDT by propagating join
state into the core. The P-Group for that join is extracted from the MDT Join TLV. If
SSM is not activated or the P-Group is not in the SSM group range, P-PIM-SM performs
a <*, G> join towards the RP for that P-Group.
If SSM is activated and the P-Group is in the SSM group range, P-PIM-SM performs
an <S, G> join towards the P-Source, where the P-Source address is the SA of the
MDT Join TLV.
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Creating Multicast VPNs
JUNOSe 11.1.x Multicast Routing Configuration Guide